Method for applying an elastic band onto a moving web

ABSTRACT

A moving web is folded at predetermined lengths at its opposite side portions so that the opposite side portions are opposed to each other at a predetermined angle with its central portion. Then part of each of the opposite folded portions is outwardly folded. These foldings occur so that a first folding line and a second folding line being opposed to each other at each side of the web include portions in non-parallel relationship. Elastic bands are affixed onto the web along the second opposite folded portions longitudinally and substantially in parallel to each other. When the web is flattened from the folded condition, the paired elastic band affixed onto the web at its oppsite sides each has a diagonal orientation symmetrically with respect to the direction in which the web moves.

BACKGROUND OF THE INVENTION

The present invention relates a method and an apparatus to affixlongitudinally an elastic band pair onto a moving web as a primarycomponent of a continuous article along opposite sides of said web sothat said elastic band pair may be disposed on the web at leastpartially in a non-parallel relationship to each other.

The present invention is applicable,, to the production of disposablearticles placed on the crotch area of the human body and provided withelastic bands to assure fitness around the legs, for example, a diaper,diaper cover or training pants for babies, thereby to affix said elasticbands onto such article on opposite sides of the crotch area in adiagonal, curved or non-parallel disposition.

To obtain the desired fitness around the legs of user and thereby tominimize possible leakage of excretions, for example, in a disposablediaper or pants, there have already been proposed methods and theapparatuses for affixing the elastic band onto such article on oppositesides of the crotch area in a diagonal or curved, i.e., non-paralleldisposition.

In such prior art, the inventive concepts have been often involved intothe means to feed the elastic band to a moving web as the primarycomponent of the continuous article and to affix this elastic band ontothe web.

However, to construct said means so that the elastic band can be affixedonto the web in a non-parallel disposition, for example, a diagonal orcurved disposition, the mechanism of such means is necessarilycomplicated and it is difficult for such a complicated mechanism to becontinuously operated at a high speed so that the elastic band may beaffixed, through the entire length of the web, at predeterminedpositions in an orderly and uniform manner. In view of suchdifficulties, the elastic band has usually been affixed onto thedisposable diaper at opposite sides of the crotch area, regardless ofthe teachings of prior art. It will be readily appreciated that a diaperprovided with the elastic band in such a parallel disposition can notprovide satisfactory fitness around the legs of user. This not onlydeteriorates appearance and feeling but also may permit leakage ofexcretions.

The object of this invention is to overcome the problems as set forthabove with a relatively simple method and apparatus.

THE INVENTION

The above-mentioned object is achieved by a method and apparatus forcontinuously feeding web as a primary component of the continuousarticle to a process to combine said web with longitudinally elasticband and for affixing said elastic band onto said web, respectively asfollows:

Method comprising steps of:

at said process of combination, folding (first folding) a predeterminedlength of said web (at least corresponding to a single individualarticle) at opposite side portions thereof so that said opposite sideportions are opposed to each other at a predetermined angle with acentral portion of said web and then partially folding (second folding)each of said opposite folded portions outwardly, these foldingsoccurring so that a first folding line and a second folding line beingopposed to each other at each side of said web include portions innon-parallel relationship and said folding defines a deformation of theweb out of the plane of that web;

affixing the elastic band onto said web along a portion defined betweensaid second folding line and the outermost edge at each side of said webparallel to the longitudinal direction of said web, longitudinally andsubstantially in parallel to the elastic band on the other side of saidweb; and

flattening said web from said folded condition so as to achieve adesired final disposition of said elastic band that said elastic bandaffixed onto said web at opposite sides thereof each has a diagonalorientation symmetrically with respect to the direction in which saidweb travels.

Apparatus comprising:

a support having unevenly contoured peripheral segments in conformitywith which said web is folded and curved, each of said unevenlycontoured peripheral segments including a grooved central area defininga slope area gradually rising from at least one end of a segment middleportion to the other end in the same direction as said web travels,rising edge areas formed along opposite sides of said grooved centralarea, and a rising end area continuous with the highest end of saidslope area and having substantially the same height as that of saidrising edge areas; and

means to affix paired elastic band substantially in parallel to eachother onto said web at portions thereof lying immediately on saidopposite rising edge areas while said web is pressed against and foldedin conformity with said unevenly contoured peripheral segment.

Apparatus comprising:

a support having unevenly contoured peripheral segments in conformitywith which said web is folded and curved, each of said unevenlycontoured peripheral segments including a rising central area defining aslope area gradually falling from at least one end of a segment middleportion to the other end in the same direction as said web travels,stepped down edge areas formed along opposite sides of said risingcentral area, and a falling end area continuous with the lowest end ofsaid slope area and having substantially same height as that of saidstepped down edge area; and

means to affix paired said elastic band substantially in parallel toeach other onto said web at portions thereof lying immediately on saidopposite stepped down edge areas while said web is pressed against andfolded in conformity with said unevenly contoured peripheral segment.

According to the method of this invention, as will be apparent from theaforegoing description, the opposite sides of the web are folded alongthe desired lengths thereof so as to form first and second foldinglines, said first folding lines and said second folding lines beingpartially in non-parallel relationship, and the paired elastic bands arefed and affixed onto the web at the top surfaces of the opposite edgescorresponding to the opposite second folded portions substantially inparallel relationship to each other so that said paired elastic bandsmay be disposed in non-parallel relationship, (i.e., symmetricallydiagonal) when said web is flattened from said folded condition. Thisunique feature advantageously eliminates the need for the elastic bandfeeding/holding device, for example, to have a complicated mechanism forthe deflection of said elastic band and enables the paired elastic bandto be continuously fed and affixed in parallel relationship onto theweb, although the final result is that said paired elastic bands will bedisposed on said web in a non-parallel relationship.

According to the apparatus of this invention, on the other hand, theunevenly contoured segments in conformity with which said web is foldedand curved are formed along the supporting periphery of the support forthis web. This unique feature advantageously simplifies a mechanism todispose said paired elastic band on said web, eliminates possibility oftroubles and malfunctions, and enables both the web and the elastic bandto be operated at a high speed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view schematically showing a rotatable support as anapparatus of the invention used to execute a method of the invention;

FIG. 2 is a fragmentary sectional view showing a part of said apparatus;

FIG. 3 shows an unevenly contoured peripheral segment of said support ina cross-section taken along a line III--III in FIG. 2;

FIG. 4 shows said unevenly contoured peripheral segment in across-section taken along a line IV--IV in FIG. 2;

FIG. 5 is a fragmentary perspective view showing web as pressed againstand thereby shaped in conformity with said unevenly contoured peripheralsegment;

FIG. 6 is a view similar to FIG. 5, showing said web after shaped andhaving pieces of elastic band affixed thereonto;

FIG. 7 is a plan view showing said web after shaped and having pieces ofelastic band affixed thereonto;

FIG. 8 is a view similar to FIG. 7, showing said web after shaped andhaving pieces of elastic band affixed thereonto, but as having beenflattened;

FIG. 9 is a side view partially showing another embodiment of therotatable support;

FIG. 10 shows an unevenly contoured peripheral segment of said rotatablesupport in a cross-section taken along a line X--X in FIG. 9;

FIG. 11 shows said unevenly contoured peripheral segment in across-section taken along a line XI--XI in FIG. 9;

FIG. 12 is a sectional view illustrating an embodiment of the methodaccording to the present invention wherein the unevenly contouredperipheral segements of the support, one of which is shown by FIGS. 1and 2 are utilized but the pieces of elastic band are affixed onto theweb at positions different from those as in FIG. 2;

FIG. 13 is a plan view showing the web after pressed against, therebyshaped in conformity with said unevenly contoured peripheral segmentsone of which is shown by FIG. 12, and then having the pieces of elasticband affixed thereonto;

FIG. 14 is a view similar to FIG. 13, showing said web thus press-shapedand having the pieces of elastic band thereonto, but as having beenflattened; and

FIG. 15 and 16 are plan views illustrating another embodiment of themethod according to the present invention wherein a configuration ofsaid unevenly contoured peripheral segment and/or positions at which thepieces of elastic band are affixed onto the web may be varied toposition the pieces of elastic band in a correspondingly varied pattern.

PREFERRED EMBODIMENTS OF THE INVENTION

The invention will be described more in detail, by way of example, withreference to the accompanying drawings.

Referring to FIGS. 1 through 4, there is shown an apparatus forexecution of the method according to the invention. The apparatuscomprises a circular support 1 that is rotatable around a central axis0. The support 1 has at predetermined intervals along its peripherygrooved central areas 3, rising edge areas 2 provided on opposite sidesof the respective grooved central areas 3 and having their inner wallsextending substantially in parallel with each other and substantially inperpendicularity to top surfaces of the associated grooved centralareas, and relatively shallow grooved areas 4 extending between theadjacent grooved central areas 3 and presenting circular arcs eachdefined by a radius slightly shorter (or lower) than that of said risingedge areas 2. It should be understood here that such shallow groovedareas 4 may present their circular arcs defined by the same radius asthat of said rising edge areas 2 and these areas 4 will be referred tohereinafter as rising end areas 4. Each of said grooved central areas 3has slope areas 6 gradually rising from a longitudinally middle position5 of the segment towards opposite rising end areas 4.

Closely around support 1, having along its outer periphery unevenlycontoured peripheral aforementioned segments, there are provided threeguide rollers 7a, 7b, 7c to guide a press-down belt 8 so that said belt8 will be pressed against the outer periphery of said support 1 as saidbelt 8 travels in synchronization with said support. There are providedpressure rollers 9a, 9b in opposition to the top surface of the groovedcentral area 3 in order to urge the belt 8 against said top surface andthese rollers are supported by suitable means with the interposition ofsprings, so that said rollers may smoothly follow both said groovedcentral area 3 and said rising end areas 4 regardless of a difference inheights of these areas. Closely around the support 1, there areadditionally provided guide rollers 11a, 11b, and guide roller 11a beingadapted to feed web 10 as the primary constituting member of thecontinuous article, and said guide roller 11b being adapted to take saidweb 10 out from the support.

As shown in FIGS. 1, 2 and 5, the web 10 is fed to the outer peripheryof the support 1 which is rotating in a direction as indicated by anarrow and the pressure rollers 9a, 9b cause the belt 8 travelling in adirection as indicated by an arrow to press said web 10 against thegrooved central area 3 and the associated rising end areas 4 so thatsaid web 10 is folded and curved in conformity with these areas.

There is provided above or laterally of the opposite rising edge areas2, though not shown, a device operating synchronously with the support 1to cut a continuous elastic band (not shown), stretched and applied withsuitable adhesive into pieces of predetermined length, and to feed eachof these cut pieces intermittently onto the web 10. Particular types ofthis cutting device are not critical so long as the device functions inthe manner mentioned above and it may be of the prior art. This deviceenables the pieces of elastic band 12 to be affixed onto the web 10substantially in a parallel relationship with each other along the topsof said opposite rising edge areas 2 which extend along opposite sidesof the respective slope areas 6.

As seen in FIGS. 6 and 7, in a section of the web 10 that has beenshaped and provided with the pieces of elastic band 12 affixedthereonto, opposite first folding lines 13 as well as opposite secondfolding lines 14 extend substantially in parallel to each other,respectively, and respective first folded portions 16 are substantiallyperpendicular to a central portion 18 and respective second foldedportions 17 are substantially perpendicular to said first foldedportions 16. However, when this central section of the web 10 isflattened, the opposite second folding lines 14 are moved out of theparallel relationship and, accordingly, the opposite pieces of elasticband 12 become disposed in a non-parallel pattern as shown by FIG. 8.Such pattern of the elastic band pieces 12 will be repeatedlongitudinally of the web 10 and, once the continuous article has beencompleted, the web 10 will be cut along a middle line 15 between eachpair of the longitudinally adjacent patterns of the elastic band pieces12 into individual articles.

As has previously been mentioned, the pieces of elastic band 12 areintermittently affixed onto the web 10 in this embodiment. However, itis also possible for the continuous elastic band 12 to be intermittentlyapplied with adhesive leaving portions which are not affixed onto theweb 10, then said continuous elastic band 12 is affixed at said portionsapplied with adhesive onto the web 10 and cut at said portions having noadhesive so that these portions contract upon said cutting.

FIGS. 9 through 11 show another embodiment in which the circularrotatable support 1 has along its outer periphery unevenly contouredperipheral segments each basically presenting a configuration that is areverse to that in the support 1 shown by FIGS. 1 through 4. Morespecifically, this support 1 of FIGS. 9 through 11 has a rising centralarea 3a, stepped down edge areas 2a and grooved end areas 4a atpositions corresponding to said grooved central area 3, said rising edgeareas 2 and said rising end areas 4, respectively, of the previousembodiment. The rising central area 3a gradually falls from a segmentmiddle area 5a towards the opposite grooved end areas 4a, formingrespective slope areas 6a. The web 10 is pressed against the outerperiphery of this support 1 so as to shape respective portions of theweb 10 in conformity with the respective unevenly contoured peripheralsegments of the support 1 and pieces of elastic band 12 are affixed ontothe web 10 substantially in parallel to each other along the portions ofthe opposite grooved edge areas 2a that extend along opposite sides ofthe respective slope areas 6a. The pieces of elastic band 12 will formthe pattern as shown by FIG. 8 when the web 10 is flattened.

FIGS. 12 through 14 show an embodiment in which the support 1 of FIGS. 1through 4 is utilized but the pieces of elastic band 12 are affixed ontothe web 10 in a pattern different from that shown by FIG. 8. Accordingto this embodiment, the pieces of elastic band 12 are affixedsubstantially in parallel relationship onto the web 10 along portionsthereof lying on each rising end area 4 and the opposite rising edgeareas 2 extending along opposite sides of the slope areas 6 extending toand from this rising end area 4. When the web 10 is flattened, thepieces of elastic band 12 form a pattern in which the bow-shaped piecesof elastic band 12 are disposed in non-parallel relationship. Accordingto this embodiment, instead of disposing the pieces of elastic band 12for each pair of individual articles on said portion of the web 10 asshown in FIGS. 2, 5 and 6, the pieces of elastic band 12 for a singleindividual article are disposed on said portion of the web 10.Accordingly, circumferential lengths of the grooved central area 3 andeach rising end area 4 in this support 1 should be shorter than those inthe support 1 of FIGS. 1 through 4.

As will be readily understood from the foregoing description,configuration of the unevenly contoured peripheral segments and/orpositions at which the elastic band pieces 12 are affixed onto thefolded and curved web 10 may be selected to vary a non-paralleldisposition of said elastic band pieces 12 on opposite sides of theflattened web 10, for example, as shown by FIGS. 15 and 16.

Although the circular rotatable support 1 having along its outerperiphery the unevenly contoured segments in conformity with which theweb 10 is folded and curved has been described above particularly withrespect to two preferred embodiments, the object of the presentinvention can be also achieved by a circular arcshaped or a plate-likesupport which is preferably movable in the same direction as the web 10travels in synchronization with said web 10, but may be stationary.

What is claimed is:
 1. A method for continuously feeding a web as aprimary component of continuous article to a process to combine said webwith longitudinally elastic band and for affixing said elastic band ontosaid web, said method comprising the steps of:at said process ofcombination, folding (first folding) a predetermined length of said webat least corresponding to a single individual article at opposite sideportions thereof so that said opposite side portions are opposed to eachother at a predetermined angle with a central portion of said web andthen partially folding (second folding) each of said opposite foldedportions outwardly, these foldings occurring so that a first foldingline and a second folding line being opposed to each other at each sideof said web and include portions in non-parallel relationship and saidfolding defines a deformation of the web out of the plane of the web;affixing the elastic band onto said web along a portion defined betweensaid second folding line and the outermost edge at each side of saidweb, parallel to the longitudinal direction of said web andsubstantially in parallel to the elastic band on the other side of saidweb; and flattening said web from said folded condition so as to achievea desired final disposition of said elastic band, that said elastic bandaffixed onto said web at opposite sides thereof each has a diagonalorientation symmetrically with respect to the direction in which saidweb travels.
 2. A method as recited in claim 1, wherein said respectivefirst folding lines extend substantially in parallel to each other andsaid respective second folding lines extend in non-parallel to saidrespective first folding lines at the opposite sides of said web.
 3. Amethod as recited in claim 1, wherein the portions folded along saidrespective first folding lines are substantially perpendicular to thecentral portion defined between said respective first folding lines. 4.A method as recited in claim 1, wherein the portions folded along saidrespective second folding lines are substantially perpendicular to saidportions folded substantially perpendicularity to said central portion.5. A method for attaching opposed pairs of elastic bands (12) to acontinuous web (10) which comprises:(a) longitudinally feeding acontinuous web (10) over at least a portion of the circumference of arotating support member (1) that has at least one unevenly contouredsurface portion (3, 3a), located on its periphery, (b) pressing said web(10) against each unevenly contoured surface portion (3, 3a) as the webpasses over each unevenly contoured surface portion to thereby deformthe web so that the central portion (18) of said web is deformed out ofthe plane of the web as it existed prior to contacting said rotatingsupport member (1), such pressing thereby forming on each side of thedeformed central portion (18) of the web(i) a first folding line (13)and (ii) a second folding line (14) located outwardly with respect tosaid first folding line (13) and in a partially parallel relationship tosaid first folding line (13), (c) affixing an elastic band (12) to saidweb (10) along that portion of each side of the web that extends betweensaid second folding line (14) and the outermost edge of that side of theweb, each pair of opposed elastic bands (12) thus affixed beingsubstantially parallel to each other and substantially parallel to thelongitudinal direction of said web, and (d) applying a flatteningpressure to said deformed web (10) so that in its flattened conditioneach opposing pair of elastic bands (12) are no longer in a completelyparallel relationship to each other.
 6. The method of claim 5 whereinthe area between said first folding line (13) and said second foldingline (14) constitutes a first folded portion (16) that is disposedgenerally perpendicularly to the bottom of said deformed central portion(18).
 7. The method of claim 6 wherein the area between each secondfolding line (14) and the outermost edge of that side of the webconstitutes a second folded portion (17) that is generally perpendicularto said first folded portion (16).
 8. The method of claim 7 wherein saidelastic bands (12) are applied to at least a portion of said secondfolded portion (17).